This was tried by ZyX-I when the Neovim project was started. AFAIK they managed to create an alternative parser for Vimscript, but the transpiler was never finished (or productionized?), I think due to incompatibilities that are hard to avoid. Some relevant issues:
- https://github.com/neovim/neovim/issues/170
- https://github.com/neovim/neovim/issues/387
- https://github.com/neovim/neovim/issues/392
- https://github.com/neovim/neovim/issues/801